Bifilar triode transistor



May 1, 1956 H. J. MOCREARY 2,744,219

BIFILAR TRIODE TRANSISTOR Filed June 11, 1949 2 Sheets-Sheet l FIG. 2

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INVEN HAROLD J. M CR Y ATTORNEY y 1956 H. .1. M CREARY 2,744,219

BIFILAR TRIODE TRANSISTOR Filed June 11, 1949 2 Sheets-Sheet 2 FIG. 4

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u.! o E E w 2O 3O 4O 5O 6O INPUT RESISTANCE INVENTOR. HAROLD J. M CREARY ATTORNEY Electric Laboratories, Inc., Chicago, iii, a corporation of'Delaware Application June. 11, 1949, Serial No. 98,605 8 Claims. (Cl. 317-235) This invention relates to electrical translating devices and' more particularly to those of the solid. contact type employing a unidirectional semi-conductive element, said contacts comprising dual files of. contact elements and hence. the name, bifilar triode.

An object of the invention is to provide a non-thermionic, non-vacuum rectifier and amplifier.

Another object of the invention is to achieve these ends with a comparatively simple and eificient mechanism, which will lenditself readily to low cost production means.

A general discussion of past and presently used termslatingdevicesis madein my co-pending application Serial No. 98,606 filed June 11, 1949, now Patent 2,677,079, and reference thereto will supply ample background for a description of the present invention likewise.

A feature of this invention constitutes the close spacing and fixed position of the contact elements on a semiconductive element by reason of which amplification and translation is achieved.

" Another feature. of this invention lies in the creation of a translating device which requires no filament heating currentsupply, and. accordingly no Warm up time.

And still another feature of my invention lies in its adaptability to small and compact form.

A. further feature of this. invention is the use of dual files of contacts arranged so as. to give a maximum number of contact points and covering virtually the entire surface or the semi-conductor.

Thesefand other features which will become apparent upon further reading of the specification, and together with. the accompanying drawings, will be pointed out and explained fully hereinafter.

In! the accompanying drawings, Fig. 1 is a front view of the bifilar triode translating device.

' Fig. 2 is an end view of thedevice.

. Fig. 3 is. a partial enlarged cross section along the line iza. in Figure-.2 showing the relationship of the resilient tubing, bifilar winding, exposed line contacts: thereof and the semi-conductive translating element.

Fig. 4 is. a test. circuit containing the bifilar triode in circuit symbol, and a potentiometer 10, to vary the re sistance. in the input portion of the circuit as. well as an ammeter and volt meter in both input and output portions of said. test circuit, said meters being labelled A1, V1 and A2, V2 respectively.

Figures 5 and 6 are graphs of data obtained by varying the resistance of the potentiometer in Fig. 4 and taking readings on said meters in Fig. 4.

Referring again to Fig. l of the drawings for a detailed description of the construction and operation of the bifilar triode transistor, a metalconductor strip 1 is bent 180 into a. U-shape. Over the end of one of the legs of the U-shaped strip is placed a resilient tube or plastic sleeve 2 which extends part of the way up the leg enveloping and insulating the end portion thereof. This tubing or sleeve should fit snugly to obviate slippage. Two finely insulated wires of small diameter are wound simultane- United States Patent 0 while the free end of rod 9 is in contact with the inner ICC 2- ously side by'side over the central portiom of the insulator tubing. Such a winding may be accomplishedin thesame manner as the first layer in a bifilar non-inductive. sole noid. This winding 3 is terminated by clipping the pair at the desired point, being careful to insulate these two ends from one another. A sealing layer as of cellulose or plastic cement 4 is applied to one. side of the winding 3 to seal and holdit in place. The other two. ends of the winding are. brought out throughthis. layer 4. and individually electrically andmechanically afiixedto a correspond.- ing lead wire 5 and 6. Lead wire. 7 is, similarly aifixed to strip 1.

The surface of the winding between the legs of stripv 1 is skinned or cleaned olfas by stroking along the. files with a very fine emery or crocus cloth very lightly. The result will be uniformly spaced apart. lines of exposed contacts.

In one embodiment of this. invention standardv #44 enameled copper wire is used for the single. layer bifilar winding. Since #44 enameled wire is. only .001 inch in diameter, these parallel line contacts are only .001. inch apart.

A semi-conductive crystal element 8. composed sub.- stantially of the element germanium and a mounting rod 9 one end of which is aflixed electrically and. mechanically to the crystal, are placed between the legs of. U- shaped strip 1 so that an. exposed crystal surface. is, in contact with the line contacts of the bifilar winding 3 surface of the opposite leg of, strip. 1-. The rod 9 is of suflicient length so that co-operating with. the resilience of sleeve 2 and the flexibility of wire winding 3, the line contacts of winding 3 are firmly held in parallel. line contact over the entire crystal surface, while. the free end of rod 9 is held in firm, electrical contact. with the. inner surface of the opposite leg of U-shaped strip 1. This is clearly depicted in the end cross-sectional. viewportrayed in Fig. 2. Figure 3 is. a cross-sectional view in a plane perpendicular to-that, of Fig. 2 and cutting the winding 3. It shows the, relationship. of the. bifilar wires laying side by side between'resilient. sleeve 2, and crystal 8 and points of contact of the. linecontactsiup on crystals.

A. bifilar transistor as detailed hereinbefore is depicted in symbol in Fig. 4 with its component elements connected intoa test amplifying. circuit It will be in. the interest of clarity to describe the function. of. this. transistor in respect to its operation in such.- a. circuit,

One of the bifilar Wound wires is called an emitter. wire and is associated with, the input. circuit in the. amplifying arrangement while thev second bifilar wound wire is. called a collector and is associated with the outputcircuit. The metal strip 1 electrically connected. to. the. semi-conductor 8 forms the third element in triode, and is. called the base electrode.

A potentiometer It is. provided. in the input circuit. so that. the resistance therein may bev varied: Potential'jfor the input circuit is provided from battery 11. meter and voltmeter, A1 and V1 are. also included. in the input circuit. The input circuit. is. traced from. crystal 8 through emitter wire ammeter A1, potentiometer 10, battery 11 to base electrode 1.. Voltmeter. V isbridged across emitter wire and baseelectrode 1.. The. out.- put circuit is traced from crystal 8 through collector wire 0, ammeter A2, fixed load resistance 12,. battery 13v to base electrode 1. Output voltmeter V2. is bridged. across collector wire (0) and base electrode 1.]

Data obtained from readings on these meters is plotted in graph form in Figs. 5 and 6. Fig. 5 is a graph of voltage in the input circuit, V1, as abscissa plotted against output voltage V2 as ordinate. As the curve shows, if voltage is recreased in the input circuit from the neighborhood of 1 volt to the vicinity of zero volts, the output voltage increases from 5 to nearly 9 volts evidencing a decided voltage gain.

In Fig. 6 with input voltage 11 constant, the poteniometcr is varied and the resistance in the output circuit is calculated from readings on the meters V2 and A2 by the equation Input resistance in ohms is plotted as abscissa and output resistance in ohms as ordinate. The resultant plot shows that the resistances are a linear function of one another, an increase of ohms resistance from to ohms in the input circuit results in an output resistance increase of nearly 200 ohms. Accordingly a decreased input re sistance affords a power amplification in the output circuit taken off the load resistor 12 if it remains constant.

Likewise, if the bifilar triode transistor is substituted for v a conventional triode vacuum tube in an amplifying stage of a standard superheterodyne circuit, as for example an intermediate frequency amplification stage, a weak signal impressed upon the input circuit will travel through the emitter winding exciting semi-cylindrical fields in the c1ystal about each emitter line contact. The magnitude of these fields will control the amount of amplification of this signal translated in the collector circuit. The spacing is such that the collector line contacts lie within the field excited by the adjacent emitter line contact. In such a circuit due to the close proximity and spacing properties of fine insulated wire, emitter and collector contact points may be had in infinite number on a semi-conductive crystal in such a manner as to have said signal translated into the circuit associated with the collector Wire in a rectified and greatly amplified form.

What is claimed is:

, I. In a translating device, a semi-conductive translating element with a base electrode attached thereto; and an emitter and a collector element comprising finely insulated wires of small diameter arranged in a plurality of parallel contiguous rows, crests of said rows being arranged in a plane, the relationship of said rows one to another being such that every other row constitutes said emitter element and therebetween, every other row constituting said collector element, the insulation on said crests in said plane being removed to expose a plurality of parallel line contacts, and a surface of said semi-conductive translating element abutting said plane forming a plurality of line contacts engaging said semi-conductive translating element.

2. In a translating device substantially as described in claim 1, the spacing apart of said line contacts one from another being at all points thereon uniform and said spacing being determined by the product of two times the sum of the radius of said emitter and collector elements plus the thickness of the insulation thereon.

3. In a translating device, a semi-conductive translating element with a base electrode attached thereto, a metal strip supporting said electrode and said element, a short length of resilient non-conductive material fitted snugly over one end of said strip, an emitter and a collector element comprising fine flexible wires of small diameter and insulated from one another in a plurality of contiguous parallel rows laying on a surface of said resilient material, said rows being every other one the emitter element and therebetween every other one the collector element, means to press said semi-conductive element against said plurality of rows of said emitter and collector elements; the resiliency of said material, flexibility of said wires and said means co-operating to permit a plurality of line con- 4 tacts of said emitter and collector wires on said semiconductive translating element. r

4. In a translating device, a U-shaped metallic strip, a sleeve of non-conductive material snugly fitting over one leg of said U-shaped metallic strip, the material of said sleeve having a resilient characteristic, an emitter and a collector element comprising fine flexible wires arranged in a plurality of parallel rows in a single layer winding around said sleeve, said wires being finely insulated one from another in said plurality of rows, said rows being every other one the emitter element and therebetween every other one the collector element, a semi-conductive translating block supported by said U-shaped metallic strip, a rod electrically and mechanically affixed to one surface of said semi-conductive block, said translating block and affixed rod being positioned between the legs of said U-shaped metallic strip so that the free end of said rod is in contact with the inside surface of one leg of said metallic strip and a surface of said translating block is in contact with the plurality of rows of said emitter and collector elements, the length of said rod being such as to firmly hold said semi-conductive translating block in a plurality of line contacts with said emitter and collector elements.

5. In a translating device, a U-shaped metallic strip, a sleeve of non-conducting resilient material snugly fitting over one leg of said strip, an emitter and a collector element comprising standard enamel insulated copper wires of small diameter wound in a plurality of rows in a single layer around said sleeve, said rows being every other one the emitter wire and therebetween, every other one the collector, a surface of said winding having the insulation removed therefrom to expose a plurality of parallel line contacts uniformly spaced one from another, a semi-conductive translating block and rod atlixed thereto supported by said U-shaped metallic strip, said translating element and said rod positioned between the legs of said strip so that said rod is in contact with the other leg thereof while a surface of said translating block is in contact with said surface of the windings forming said plurality of line contacts.

6. In a translating device substantially as described in claim 5, said semi-conductive translating block composed substantially of the element germanium.

7. In a translating device, two wires wound in a single layer winding with one of said wires alternating with the other of said wires to form alternate rows, fine insulation between said rows thereby insulating said one wire from said other wire, non-insulated surfaces on said wires forming a plurality of spaced apart line contacts on one surface of said winding and a semi-conductive translating element in contact with said plurality of line contacts, the spacing of said line contacts on said semi-conductive translating element being due to the arrangement of said wires in said single layer winding and the fine insulation between the rows thereof.

8. In a bifilar triode translating device, the elements of the triode device being a collector and emitter comprising two wires wound in a single layer winding, every other row in said winding being said emitter and therebetween, every other row being said collector, insulation separating the rows of said emitter and collector one from another; a semi-conductive translating element and a metal base electrode attached thereto, said emitter and collector rows being in a plurality of spaced apart line contacts in engagement with said semi-conductive translating element.

References Cited in the file of this patent UNITED STATES PATENTS 2,524,035 Bardeen et a1 Oct. 3, 1950 

